Text and Data Mining valid from 2019-04-16
First Online: 16 April 2019
Compliance with Ethical Standards
: No external funding was used in the preparation of this manuscript.
: Robert Duffy, Tara Jennings, Saritha Kartan, Andrew Song, Wenyin Shi, Pierluigi Porcu, Onder Alpdogan, and Joya Sahu have no conflicts of interest that might be relevant to the contents of this manuscript.